Playful Machines A Facilitator s Guide to Simple Machines in the Playground

Transcription

1 Playful Machines A Facilitator s Guide to Simple Machines in the Playground

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3 A. Description of Workshop Note: This workshop has two levels: Playful Machines 1 and 2 Appropriate Age/Grade for Workshop Overview of Workshop Playful Machines 1 is designed for use in Grades K-2 classrooms or with children ages 5-8. Playful Machines 2 is designed for use in Grades 3-5 classrooms or with Power Play 1 Welcome to the science of the school playground! In this workshop, students examine simple machines by incorporating levers, wheels and axles, and inclined planes into a playground environment. Simple machines will be transformed into real objects that are familiar to the children. Power Play 2 Welcome to the science of the school playground! In this workshop, students examine simple machines by incorporating levers, wheels and axles, and inclined planes into a playground environment. Pulleys and gears will be investigated through hands-on activities. Simple machines will be transformed into real objects that are familiar to the children. Science Topics Simple Machines Energy Forces Overall Objectives To understand the names and examples of simple machines. To learn the difference between simple and complex machines. To learn the importance of machines in our everyday lives. Playful Machines - Page 3 of 20

4 B. How to Run This Workshop Physical Requirements You will need a large classroom with a demonstration area at the front. Arrange desks so that you can put groups of students together to share materials. Materials and Set-up Activity #1 Roundabout *Cut-out cardboard circles (1 per child) *Brass fasteners (1 per child) *Pipe-cleaners (1 per child) *Styrofoam base (1 per child) *Clear tape (20-25 rolls) CHOICE: Only use Activity #4 and #5 if you are doing Playful Machines 2. Activities can be done in any order. *Consumable items Playful Machines - Page 4 of 20 Activity #2 Slide *Pipe-cleaners (1 per child) *Short pipe-cleaners (2 per child) *Craft sticks (3 per child) *Clear tape (use same as for Activity #1) Slide task card Activity #3 Teeter-Totter Lever parts to put on blackboard Activity #4 Pulleys 3 single pulleys same size Activity #5 Gears Plastic Gears and bases Sample lever pictures 1 large single pulley Gear task card *Pipe-cleaners (2 per child) *Craft sticks (3 per child) *Straw (1/4 per child) 2 double pulleys Thick string or rope Coloured tape Round-about task card *Clear tape 4 water bottles filled with same amount of water Lids need eye-hooks and washers Teeter-totter task card LEVER TESTING Beams Fulcrums Weights 2 metre sticks with four small hooks to hang pulleys from 2 hooks to attach pulleys on #3 and #4 to water bottles Number labels for water bottles (#1, #2, #3, #4). Pulley task card or poster Wrap-Up Simple machine picture cards

5 BRIGHT IDEA: Clear tape, pipe-cleaners and craft sticks are used for almost all activities. Put these out on tables before beginning the workshop. BRIGHT IDEA: This activity works best if the students do the same activity at the same time (no stations). Timing of Activity Part of Workshop: Suggested Timing: Overall: General Introduction 5 min. 5 min. Introduction to Topic 10 min. 15 min. Activities #1, #2, #3 15 min. each (x3) 60 min. Lever Testing 15 min. 75 min. (OPTIONAL) Activities #4, #5 15 min. each (x2) 105 min. (Playful Machines 2) Wrap-Up 10 min. 110 min. C. Introduction to Topic Objectives of Introduction To provide a basic background of machines simple and complex. To provide examples of simple machines that children can relate to. Suggested Discussion, Q & A What is a machine? Car, washing machine, crane, tools A machine is a device that enables you to do difficult mechanical work by changing the direction or the size of the force (load) required to do the work. In some cases, a machine may do work faster than is capable without the machine. Often the force exerted is spread out over a greater distance. There are special machines we call simple machines. Simple machines are not big machines like cranes and cars (refer to examples Playful Machines - Page 5 of 20

6 students may have given you already). Simple machines help us to do work; however they do not have any power of their own (no engines, etc). They are just what their name says Simple! What are the different types of simple machines? There are three main simple machines, including the lever, wheel and axle, and inclined plane. Other simple machines, including the pulley, gear, screw and wedge are modifications of the three basic simple machines (Pulleys and gears are modifications of wheels and axles, screws and wedges are modifications of inclined planes). CHOICE: If this is the first time the class is learning about simple machines, skip the next part and move on to the difference between simple and complex machines. What is a commonly used example of a lever? See-saw (teeter-totter), arm, balance (scales) A lever helps us do work by pivoting an object about an axis. What is a commonly used example of a wheel and axle? Roundabout, toy cars, bicycles, doorknob A wheel and axle help us do work by moving or lifting loads. What is a commonly used example of an inclined plane? Slides, ramps outside of buildings, slopes An inclined plane helps us do work by moving objects up and down. What is a commonly used example of a pulley? Crane, flagpole, mini-blinds, curtain rods A pulley helps us do work by moving things up, down and across What is a commonly used example of gears? Clocks, bicycle, water wheel A gear helps us to do work by moving things in a circular motion. What is a commonly used example of a screw? The car jack, screw, jar lids A screw helps us do work by holding things together and/or lifts things. Playful Machines - Page 6 of 20

7 What is a commonly used example of a wedge? The head of an axe, snow plow, nail, pin, knife A wedge helps us do work by spreading or cutting an object apart. What is the difference between a simple machine and a complex machine? A simple machine is a single function device that can do work. A simple machine does not have any source of power other than your body. A complex machine is a combination of simple machines that perform together to do work. Complex machines may contain a source of power other than your body, such as a battery or a motor. D. Activities ACTIVITY #1: ROUNDABOUT (10-15 min.) Use Roundabout Task Card Objective of Activity To relate the wheel and axle to a roundabout (merry-go-round) on the playground. Suggested Instructions, Q & A The wheel & axle is an important simple machine. It is found in many things that move. A wheel is a circular, round object. An axle is a post that fits in the middle of the wheel. The wheel turns on the axle, causing movement. Working together, a wheel and axle move objects across a distance. What are some things that move and have a wheel and axle? Bicycle, roller blades, Have you ever played on a round-about (merry-go-round) at the playground? Yes That is a wheel and axle! Playful Machines - Page 7 of 20

8 The first part of our playground is going to be a round-about. DELIVERY HINT: Go over the task card with the students before they start to build their roundabout and show them an example of what they are going to make. Point out that the wheel should not be placed too close to the edge of the tray or it will hit the edge. Activity Wrap-Up Now that you've made your round-about, can you identify the wheel? Cardboard circle What about the axle? Brass fastener How does a round-about work as a simple machine? It makes your work easier. You can move many of your friends at the same time! ACTIVITY #2: SLIDE (10-15 min.) Use Slide Task Card Objective of Activity To relate an inclined plane to a slide on the playground. Suggested Instructions, Q & A An inclined plane is a kind of simple machine. An inclined plane looks like a board on an angle, with one end up in the air and the other end touching the ground. What is an example of an inclined plane? A ramp Playful Machines - Page 8 of 20

9 Where might we find an inclined plane on a playground? A slide DELIVERY HINT: Go over the task card with the students before they start to build their slide and show them an example of what they are going to make. Activity Wrap-Up What kind of simple machine is a slide? An inclined plane. How does a slide make your work easier on a playground? It uses gravity to get you from one place to another (don t have to exert as much energy) Can you think of another example of an inclined plane making work easier? One example is a moving truck. Would you want to lift a piano up onto a truck or push it on a ramp? Ramp ACTIVITY #3: TEETER-TOTTER (10-15 min.) Use Teeter-Totter Task Card Objective of Activity To relate a lever to a teeter-totter on a playground. Suggested Instructions, Q & A BRIGHT IDEA: Cut out lever parts and laminate. Stick magnets on the back. While discussing the parts of a lever, place the appropriate part on the blackboard. Playful Machines - Page 9 of 20

10 A lever is another kind of simple machine. There are 4 different parts to a lever: 1. beam (bar) 2. fulcrum (pivot point) 3. load (the thing that you want to lift) 4. effort (the force that you have to apply to lift the load) (Facilitator designs lever on blackboard with parts.) First Class Lever Load Effort Beam Fulcrum This is what's called a first class lever - the fulcrum is in the middle between the effort and the load. When you push down on one side, the other side goes up. Examples of a first class lever: teeter-totter, balance, crowbar, pliers, scissors (show sample lever pictures) CHOICE: If the class is advanced enough, you can discuss second and third class levers at this point. If not, skip down to making the teeter-totter. There is also a second class lever. It has all of the same parts as a first class lever but they are arranged differently. (Facilitator designs lever on blackboard with parts.) Playful Machines - Page 10 of 20

11 Load Effort Beam Fulcrum The effort is in the same direction as the load moves. The effort and the load are on the same side of the fulcrum with the load between the effort and the fulcrum. Examples of a second class lever: wheelbarrow, nutcracker, bottle opener, door (show sample lever pictures) Finally, there is a third class lever. It also has the same parts as a first class lever but they are arranged differently. (Facilitator designs lever on blackboard with parts.) Effort Load Beam Fulcrum The effort is in the same direction as the load moves. The effort and the load are on the same side of the fulcrum with the effort between the load and the fulcrum. Examples of a third class lever: (show sample lever pictures) fishing pole, hammer, tweezers Playful Machines - Page 11 of 20

12 We re going to build a first class lever that you might have seen in your playground. A teeter-totter! DELIVERY HINT: Go over the task card with the students before they start to build their teeter-totter and show them an example of what they are going to make. Lever Testing (Optional) Provide each pair of students with a beam, a fulcrum and some weights. CHOICE: Either read the instructions on the task card orally to the students as a group or hand out task cards to each pair. Lever Tasks: 1) Will your beam balance without any weights? Yes, as long as the fulcrum is in the middle of the beam. 2) Try balancing the beam with two weights that are the same mass! Where do the weights have to be so that the beam balances? There must be one weight on either side of the fulcrum and they must be equal distances from the fulcrum. 3) If a big person was on one side of a teeter-totter could a small person sit on the other side and life the big person up? Yes. 4) If you have a heavy weight on one side of the fulcrum and a lighter weight on the other side, can you balance the beam? Yes, the heavy weight must be close to the fulcrum and the lighter weight must be farther from the fulcrum (close to the end of the beam). 5) If you move the fulcrum, can you still balance the beam without weights? No. 6) Move the fulcrum to one end of the beam. Can you balance the beam using weights? Playful Machines - Page 12 of 20

13 Yes, the heavier weight must be close to the fulcrum and lighter weight must be close to the end of the beam. Activity Wrap-Up What kind of simple machine is a teeter-totter? A lever (first class lever) Where is the beam on your lever (teeter-totter)? The fulcrum? The load? The effort? CHOICE: Move on to the workshop wrap-up for Power Play 1. Keep going for the rest of the Power Play 2 workshop. Activity #4: PULLEYS (20 minutes) Use Task Card or Poster Objective of Activity To introduce pulleys and pulley systems. To test a fixed pulley to lift a water bottle. DELIVERY HINT: Set up the pulley station at the beginning of the workshop. Have students that are done their playgrounds early come up in small groups to try lifting the water bottles. Debrief activity as a group. Set-up Instructions: Duct tape the ends of your metre stick and hooks to two sturdy surfaces (desks, table, chairs ). Water bottle #1 should be connected to a small single pulley. Water bottle #2 should be connected to a larger single pulley. Water bottle #3 should be connected to a 2 pulley system. Water bottle #4 should be connected to a 4 pulley system. Playful Machines - Page 13 of 20

14 Suggested Instructions, Q & A Has anyone ever used a pulley before? What do pulleys help us do? A pulley is a wheel fixed to a support with a rope running over it. Pulleys help us to move objects either up and down or side to side. The purpose of a pulley is to change the direction of the force For example, if you are pulling down, it lifts the object up, if you are pulling to the right, it moves the object to the left Can you name some examples of where you could find pulleys? Elevator, clothesline, flag pole, crane, well, vacuum cleaner.. There are three different types of pulleys. A fixed pulley is a pulley that remains stationary as the load moves up and down. A good example of a fixed pulley is a flag pole. A movable pulley is a pulley that moves up and down with the load. A good example of a movable pulley is a water-well. A block and tackle has both a fixed pulley and a movable pulley. The load feels much lighter with this system. A good example of a block and tackle pulley system is a crane. There is also something called a Belt Drive system. This is when two wheels or pulleys are connected by a belt a circular strip of flexible material. A good example of this type of pulley system is a clothesline. Did everyone have a chance to try lifting the 4 water bottles with pulleys? Did you feel a difference in how hard it was to lift the 4 water bottles? Which water bottle was easiest (required the least effort) to lift? Water Bottle #4 should be the easiest to lift. It is set up with a double pulley system. Which water bottle was hardest (required the most effort) to lift? Water Bottle #1 and #2 should be the hardest to lift. It is set up with a small single pulley system that really has no mechanical advantage. Playful Machines - Page 14 of 20

15 Activity #5: GEARS (20 minutes) Use oral instructions OR Gear Task Card Objective of Activity to introduce gears to investigate how gears work Suggested Instructions, Q & A Has anyone ever used a gear before? What do gears help us do? Gears are used to transmit force to another gear with matching teeth. Can you name some examples of where you could find gears? Watch/clock, toys, bicycle, can opener, pencil sharpener We are going to investigate how gears work a little bit more by doing an activity. CHOICE: Either read the instructions on the task card orally to the students as a group or hand out task cards to each pair. Feel free to add your own inquiries/instructions depending on the level of the students understanding and the gears you have in your kit. Start turning one of your gears. Which way does the other gear turn? In the opposite direction. Turn the largest gear. Keep turning. Which gear moves faster? The small gear moves faster than the large gear. Can you count the number of teeth on the smallest gear? Can you count the number of teeth on the largest gear? What is the relationship between the number of teeth and how fast the gear moves? Students should discover that the larger the gear, the more teeth, the slower it rotates. Playful Machines - Page 15 of 20

16 Ask the students if they can think of any other questions they can answer using the gears OR add your own questions. E. Wrap-Up CHOICE: If there is time left in the workshop, you can play a wrapup game (classification of simple machines, small group activity, concentration/memory) with the simple machines picture cards. Suggested Q & A What is a machine? Something that helps us do work. What are the 3 simple machines we built on our playground? Wheel and axle, lever and inclined plane What is the difference between a simple machine and a complex machine? A complex machine is made up of many simple machines. A simple machine does not have a power source of its own (only the energy you put on it) while a complex machine may have its own energy source, like an engine. What is the important benefit of a simple machine? Did you have fun doing Science today? Thanks for having me in your class. Do you have any questions before I go? F. Glossary Efficiency Efficiency is the comparison of the useful work or energy provided by a machine or system with the actual work or energy supplied to the machine or system. Efficiency is usually stated as a percentage. Efficiency = efficient output X 100 Playful Machines - Page 16 of 20

17 efficient input Effort The effort is the force supplied to a machine in order to produce an action. Energy Energy is required to do work, which is measured in Joules (S.I.). Energy can come from synthesized sources, such as electricity and fossil fuels, or natural sources such as the human body. The original source of ALL of this energy is the sun. The sun provides the energy required for plants to create the sugars that sustain the plant. Plants are eaten by animals (humans). These animals use the energy stored in these plants to sustain themselves. Energy exists in many different forms. Energy can change forms, but it can neither be created nor destroyed. This is called The Law of Conservation of Energy. Gear A gear is a rotating wheel-like object with teeth around its rim. A gear is used to transmit force to another gear with matching teeth. Gear Train A group of 2 or more gears. Inclined Plane A slanting surface connecting a lower level to a higher level. Objects move up or down it. Lever Any rigid object which is pivoted about an axis called the fulcrum. The load and effort can be applied on either or the same side. Load The load is the object or force the machine must overcome (the weight it wants to move or the resistance it must overcome). It is this load that constitutes the mechanical work that the machine can do. Mass Mass is the amount of matter in an object. Playful Machines - Page 17 of 20

18 Mechanical Advantage The ratio of the force produced by a machine or system (load) to the force applied to the machine or system (effort). The load (L) divided by the effort (E). Perfect Machine This is a theoretical machine that has a useless load of zero, which means that there is absolutely no friction within the machine. This is impossible with the technology presently available. Machines that have a negligible useless load compared to the load of the machine can be considered to be a perfect machine. Pulley A grooved wheel with a rope or cable around it. A pulley moves things up, down or across. Screw An inclined plane wrapped around a pole. A screw holds things together or lifts. Useless Load A useless load is the force needed to overcome any frictional forces that are inherent within a machine. These frictional forces can be the interactions of the parts of a machine, or any force required to raise a part of the machine Wedge An object with at least one slanting side ending in a sharp edge. A wedge cuts or spreads things apart. Weight Weight is the pull of gravity on an object. The weight of an object can change with location. Wheel and Axle A wheel with a rod (axle) through its centre, both parts move together. Lifts or moves loads. Work Work is the force exerted to move an object. Work can be done using natural power sources (a person hand), or it can be done by human created devices that use synthesized power sources (mechanical devices that use fuel). Playful Machines - Page 18 of 20

19 G. Background Information Simple Machines Machines are devices that do work. The scientific definition of work is applying a force over a distance (W=Fxd). Many machines help us by making the work easier they won t reduce the amount of work we have to do (in fact, they may sometimes increase the amount of work) but they do make that work easier. Machines can make work easier by changing the amount or direction of either the force we have to apply or the distance over which we apply the force. Simple machines typically form the base for all other, more complex machines. The three basic types of simple machines are levers, inclined planes (ramps), and wheels and axles. Pulleys and gears are modifications of wheels and axles, screws and wedges are modifications of the inclined plane. H. Suggested Resources Websites How Stuff Works Simple Machine Page for Kids Welcome to the wonderful world of Simple Machines cs.html Marvellous Machines Books Macaulay, D. (1988). The Way Things Work. New York: Houghton Mifflin Company. ISBN: Playful Machines - Page 19 of 20

20 Posters Simple Machines Trend Enterprises From Scholar s Choice Playful Machines - Page 20 of 20